JP2018531877A - Catalytically active foam forming powder - Google Patents

Abstract

The present invention relates to the field of forming and stabilizing foams, specifically foamed construction materials such as cement. Additives suitable for obtaining mineral foams when added to the corresponding starting materials are disclosed. The present invention provides a ready-to-use product in the form of a solid particle composition comprising hydrophobized particles (1) and catalytically active particles (2) as defined in claim 1. The present invention further provides a method for producing such ready-to-use products. [Selection] Figure 5

Description

  The present invention relates to the field of forming and stabilizing foams, specifically foamed construction materials such as cement. The present invention provides a ready-to-use product in the form of a solid particle composition to obtain such construction materials. The present invention further provides such ready-to-use products and methods for producing such construction materials.

  In the classical and high-tech industries as well as in the construction industry, there is an increasing need for mineral foams with high porosity. Mineral foams have unique properties such as low specific gravity, thermal insulation, insulation, and soundproofing, they exhibit high specific strength and, depending on the chemical composition, have exceptional thermal and chemical stability. It can be presented. Foam formation is also an efficient strategy for saving raw materials and reducing component weight. An example of an application in the high temperature region is the thermal insulation of furnaces used to produce steel and glass. Foamed concrete requires much less cement compared to high density parts, helps reduce weight, or improves the thermal insulation properties of construction parts. Apart from material chemistry, the properties of mineral foams are controlled by the fine structure of the pores, especially the pore size, morphology, and distribution. Depending on the application, the pores can be in the millimeter range or on the order of hundreds of microns in size. For heat insulation applications, a closed hole structure is mainly preferred, while for soundproofing, the formation of a hole opening is beneficial. Regardless of how the microstructure needs to be designed for a given application, it is important that the foamed product does not exhibit a random gradient and is homogeneous throughout the volume. Therefore, it is absolutely necessary to control the microstructure of the foam from the formation of the foam to the end of the manufacturing process. Foams are thermodynamically unstable systems and tend to break down from the moment they are formed, so foam formation and stabilization techniques are needed that can effectively control the microstructure of mineral foams. It is said that.

  Several attempts have already been made to produce foams with a porosity of more than 60% by volume from various minerals. However, techniques that are simple to implement and robust that allow deliberate control over the microstructure of the foam should still be developed. It has further been found that known techniques for stabilizing foams can lead to significant delays in curing and / or result in degradation of mechanical properties. This is considered disadvantageous.

  Blum et al. (EP 2045227 A1) describe the formation of foam by foaming a surfactant containing a slurry of a mineral mixture containing a fast-curing cement by hydrogen peroxide decomposition. According to Blum et al. No ready-to-use foamable powder is added. The literature emphasizes that rapid curing of the material immediately after foam formation is important to prevent the foam from collapsing. Because of this disclosure, process robustness and product reliability are considered poor.

  Bean et al. (US Pat. No. 5,605,570) discloses a procedure for foaming finely ground calcium-rich vitreous slag by foaming the slurry under the decomposition of sodium peroxide. As a result of the rapid viscosity increase and rapid cure, the foam product is obtained alone. In the comparative example, it has been found that the use of surfactants that are normally mixed to improve foam formation substantially extends the cure and results in products with poor mechanical properties. Because of this disclosure, the process does not allow for the adjustment of the foam microstructure that defines the material properties.

  Brothers et al. (US2002 / 0050231) report foaming surfactants containing calcium aluminate cement formulations by injecting gas into the piping system where the cement is placed. The document discloses a final product porosity of up to 66% by volume. In thermal insulation applications, material performance increases with porosity. Therefore, a pore volume ratio exceeding 70% by volume is advantageous. Information regarding the pore structure, the possibility of controlling the pore structure, and the homogeneity of the foam is not given.

Jezequel et al. (WO2011 / 101386) describes a foamed concrete having a density of 200-800 kg / m ³ and its manufacture, which first prepares a concrete slurry and in the second step a predetermined in the slurry. By passing through a dynamic mixer used to disperse a proportion of air. The method is suitable, but requires a slurry with precisely defined rheology. Furthermore, the method is not suitable for systems that exhibit increased viscosity due to high solids loadings or formulations that contain relatively coarse agglomerates.

  Gartner et al. (WO2013 / 034567) describe particles modified with surfactants and their use in the production of stable cement-containing foams. A wide range of particles has been suggested, limestone being specifically mentioned, while very specific bifunctional surfactants are being mentioned. That document suggests that these modified particles can be employed in reduced amounts.

  Selinger et al. (FR2986790) describe foamed silicates used as mortars. In order to obtain foamed mortar, the use of surfactants as an additive rather than short chain amphiphilic molecules is disclosed therein. That document does not disclose ready-to-use additive compositions comprising particles modified with amphiphilic molecules.

  Aberle (WO 2014/009299) describes a powder mixture and a process for making dry mortar. That document addresses the goal of hydrophobizing and thickening cementitious mortars to optimize their properties for use in humid environments.

  The prior art demonstrates the need for foam construction materials and methods for their production. The prior art particularly shows the shortcomings of current methods.

  The object of the present invention is therefore to mitigate at least some of these prior art drawbacks. Thus, the present invention provides a more effective foam formation and stabilization technique. Specifically, there is a need for an easy to implement and effective foam stabilization technique that enables reliable foam formation from various minerals, especially from building material formulations. In particular, the goal of the present invention is to improve process robustness and product reliability, and to allow foam formation from mineral mixtures that do not exhibit rapid hardening.

  These objects are achieved by a composition as defined in claim 1 and a method as defined in claim 6. Further aspects of the invention are disclosed in the specification and the independent claims, and preferred embodiments are disclosed in the specification and the dependent claims.

  The invention is described in more detail below. It is understood that the various embodiments, preferences, and ranges provided / disclosed herein can be freely combined. Further, depending on the specific embodiment, selected definitions, embodiments, or ranges may not apply.

Unless stated otherwise, the following definitions shall apply herein.
As used herein, “a”, “an”, “the”, used in the context of the present invention (especially in the context of the claims), And similar terms are to be interpreted as covering both the singular and the plural unless specifically stated otherwise herein or otherwise clearly contradicted by context.

  As used herein, the terms “including”, “containing”, and “comprising” are used herein in their open, non-limiting sense. used.

  As used herein, percentages are by weight unless otherwise indicated or apparent from the context.

The invention can be better understood with reference to the drawings .

FIG. 1 provides a schematic diagram of the solid particle composition of the present invention described in more detail below. The components according to the invention are hydrophobized particles (1) (including particles (1.1) and amphiphilic molecules (1.2)) and catalytically active particles (2). Optional ingredients are indicated by the dotted line, pH adjuster (3), and additive (4). FIG. 2 provides a schematic diagram of one possible use of the composition of the present invention to obtain a foamed construction material. In this figure, i. c. Represents a composition of the present invention and s. m. Represents a known starting material such as a cementitious composition, b. a. Represents a blowing agent such as H2O2, f. c. m. Represents a foam construction material such as foam cement. As shown in this schematic diagram, the composition (i.c.) of the present invention is combined as an additive with the starting material (s.m.) and water to form a dispersion, and then to the blowing agent (b. .. a.) Is added, a foamed construction material (f.c.m.) is obtained. FIG. 3 provides an optical microscopic image of the material shown in Examples 1.1 (left) and 1.2 (right). FIG. 4 provides photographs of the construction materials shown in Examples 2.1, 2.2, 2.4, and 2.5 (left to right). FIG. 5 is an enlarged photograph of Examples 2.1 and 2.2 of FIG.

In more general conditions, in a first aspect , the present invention provides a solid particle composition comprising hydrophobized particles (1) and catalytically active particles (2), wherein the hydrophobized particles (1) are: A solid particle composition that is hydrophobized with amphiphilic molecules as defined below, and the catalytically active particles (2) as defined below. Related to things. The composition according to the invention may comprise further components, in particular a pH adjusting agent (3) and an additive (4). These compositions are suitable for producing stable foams having defined and reproducible properties when mixed with suitable starting materials before the blowing agent is injected. Thus, in order to obtain a foamed construction material (f.c.m.), the composition (i.c.) of the invention can be added to a suitable starting material (s.m.). The compositions of the invention themselves are not construction materials, so they do not result in a foamed construction material after the addition of a blowing agent. Therefore, the composition of the present invention is applied as an additive. This aspect of the invention is described in further detail below.

  The present invention provides a catalytically active inorganic powder composition. These compositions are particularly reproducible foam formation when applied in building materials, refractories, ceramics, or other particle formulations that are then dispersed in a liquid and then foamed by decomposition of the blowing agent. Designed to allow for. The foam-forming powder can be used as an inorganic additive including two main components (1), (2), an optional pH adjuster (3), and an additive (4). Component (1) is a surface-modified particle that mainly defines foaming rheology, stability, and pore size. Component (2) is a catalyst that promotes the decomposition of the blowing agent and defines the gas release rate in the system to be foamed (such as the starting material shown in FIG. 2). Optional components (3), (4) can be added to further adjust the viscosity or pH of the formulation to be foamed as well as the cure time of the water curable material.

  The advantage of this composition is that this ready-to-use foam-forming powder is applied as a single component to the starting material to be foamed. It defines all of the relevant properties of the foam, except for the porosity given by the amount of blowing agent used, so long as the system is able to stabilize the gas. As such, the composition of the present invention greatly simplifies foam formation in laboratory, industrial, and particularly field applications. Also, its use typically leads to very low concentrations of organics in the foamed end product. This is important for foamed products with targeted applications in the fire and fire resistant fields.

  The ease of handling ensures a particularly important and reproducible foam formation when the building material is foamed and typically has little time to perform complex mixing procedures. Foam-forming powder is a dry, homogeneous material and therefore exhibits a long shelf life. Application of the composition of the present invention ensures reliable foam formation and excellent foam stability. Foams prepared using the compositions of this invention exhibit a homogeneous microstructure throughout the volume. This is the key to high product quality and reliability. Therefore, the composition of the present invention can also be regarded as a functional additive. This functional additive is a ready-to-use product, for example, at a construction site.

  Solid Particle Composition: In one embodiment, the composition of the present invention is in the form of a powder, particularly a ready-to-use powder. This is beneficial because it allows direct use with common equipment and handling processes known in the industry.

  In one alternative embodiment, the composition of the present invention is in the form of granules. Such granules also allow direct use with common equipment and handling processes known in the industry.

  The compositions of the present invention are dry, so that the compositions have a low tendency to agglomerate, and furthermore, they are free flowing and / or can be poured.

  Hydrophobized particle (1): The term hydrophobized particle is known in the art, specifically a particle form in which the surface of the particle is modified with amphiphilic molecules (defined below) The solid material). Such modification is aimed at reducing the hydrophilic properties of the particles.

  Particles (1.1): The nature of the particles present depends on the intended end use of the foam to be formed and includes in particular inorganic materials.

Thus, the term includes the following exemplary inorganic materials.
-Oxides including pure and mixed metal oxides (especially aluminum oxide, silicon dioxide, spinel, cerium-gadolinium oxide, zirconium oxide, magnesium oxide, tin oxide, titanium oxide, and cerium oxide),
Hydroxides (especially aluminum hydroxide, calcium hydroxide, magnesium hydroxide, very particularly aluminum hydroxide),
・ Carbides (especially silicon carbide, boron carbide),
・ Nitride (especially silicon nitride, boron nitride),
Phosphates (especially calcium phosphates such as tricalcium phosphate, hydroxyapatite),
・ Carbonates (especially nickel carbonate, calcium carbonate (crushed limestone or precipitated calcium carbonate), magnesium carbonate),
Silicates (especially silicon dioxide, silica fume, fly ash, quartz, ground glass, slag, calcium silicate, mullite, cordierite, clay minerals such as kaolin or bentonite, zirconium silicate, zeolite, diatomaceous earth , Very particularly silica fume, clay minerals, zirconium silicates, specifically clay minerals),
-Sulfates (especially calcium sulfate).

  In a further embodiment, the term is pure, selected from the group consisting of aluminum oxide (including Al-Mg spinel), silicon dioxide, zirconium dioxide, and zinc oxide, especially aluminum oxide, silicon dioxide, and zirconium dioxide. And oxides including mixed and mixed metal oxides.

  Such inorganic materials can be synthetic materials or naturally occurring minerals. Multi-component compositions comprising a mixture of two or more of the same or different types of the aforementioned compounds may also be used.

  Careful selection of inorganic materials has been found to improve the performance and properties of foam construction materials.

  It is beneficial to select the inorganic material in such a way that the surface chemistry of the inorganic material differs from the surface chemistry of the starting material under conditions that spread to the dispersion. By doing so, the amphiphilic molecule (1.2) can be selected to selectively adsorb to the inorganic particles (1.1) rather than the starting material (sm, FIG. 2). . As a result, the solidification and strength development of construction materials are not affected by the described surface modification. Clearly, this consideration is important for solidifying construction materials such as cement.

  For materials that do not solidify or recrystallize ("mineral materials") such as alumina, zirconia, zirconium silicate, silica, etc., other considerations are more important. By selecting the combinations disclosed herein, the dispersion (FIG. 2) can be more easily produced. Specifically, it has been found that when using the composition (i.c.) of the present invention, coagulation does not occur or at least to a lesser extent.

  A particularly preferred inorganic material is calcium carbonate, either synthetic CaCO3 or naturally occurring limestone. In light of the above discussion, calcium carbonate is a starting material from the classes of calcium sulfate, calcium silicate cement, aluminosilicate geopolymer, blast furnace slag, calcium sulfoaluminate cement, hydroxyapatite, beta-tricalcium phosphate. Particularly preferred.

  Further particularly preferred inorganic materials are the group of silicates comprising silica and clay. In light of the above discussion, silicates are particularly suitable for starting materials from the classes of alumina, calcium aluminate, aluminosilicate, silica, zirconium silicate, hydroxyapatite, beta-tricalcium phosphate.

  Further particularly preferred inorganic materials are the group of oxides such as alumina and zirconia. In light of the above discussion, these oxides include alumina, calcium aluminate cement, aluminosilicate, zirconia, zirconium silicate, phosphate cement, calcium phosphate cement, aluminum phosphate binder, zirconia reinforced alumina, hydroxyapatite, Particularly suitable for starting materials from the class of beta-tricalcium phosphate.

  It has been found that the morphology of the particles is not very important. The present invention encompasses high density particles, porous particles, or a mixture of high density particles and porous particles.

  It has been found that very different shapes can be used, i.e. spherical, polygonal plate, needle, fiber, rod, cigar, single crystal etc. particles, as long as the particle size is within suitable dimensions. It was. The present invention encompasses foam-forming powders in the form of primary particles or in the form of powder compacts such as granules or pellets. The average particle size can be measured using equipment such as commonly used in powder technology such as sieving or laser diffraction. In the case of powders (primary particles), suitable particle sizes range from 30 nm to 300 μm, more preferably from 100 nm to 250 μm, even more preferably from 100 nm to 150 μm, and even more preferably from 100 nm to 100 μm. In a further embodiment, suitable particle sizes range from 100 nm to 10 μm, preferably from 100 nm to 2 μm. It was found that the particle size distribution is not very important. Good foams with a narrow particle size distribution and a wide particle size distribution can be obtained. In the case of granules or pellets, a suitable diameter range is 0.5 to 20 mm, preferably 1 to 10 mm.

  Amphiphilic molecule (1.2): The term amphiphilic molecule is known in the art and is also identified as a nonpolar part (also specified as tail or group R) and polar part (also specified as head group). The organic compound having Thus, suitable amphiphilic molecules contain a tail attached to the head group, typically by a covalent bond. Such amphiphilic molecules typically contain one tail and one head group, but can also contain more than one head group. The tail can be aliphatic (linear or branched) or cyclic (alicyclic or aromatic) and can have a substituent. Such substituents are, for example, -CnH2n + 1 (n <8), -OH, -NH3, and the like. A preferred tail is an optionally substituted linear carbon chain of 2 to 8 carbon atoms. Surprisingly, such relatively small molecules (1.2) have a significant effect on the hydrophobization of the particles (1.1) and in combination with the particles (1.1) the stability of the foam It has been found to significantly affect sex.

The head group bonded to the tail is preferably an ionic group. Examples of possible head groups are identified in Table 1 below (tail is designated R) and the corresponding salt.

  Preferred head groups are selected from carboxylic acids, gallates, amines, and sulfonates.

  Particularly preferred head groups are selected from carboxylic acids, gallates and amines (X preferably represents H or methyl).

  In an advantageous embodiment, the amphiphilic molecule reduces the surface tension of the air-water interface to a value of 65 mN / m or less at a concentration of 0.5 mol / l or less.

  In advantageous embodiments, the amphiphilic molecules have a critical micelle concentration (CMC) greater than 10 μmol / l and / or they have a solubility greater than 1 μmol / l.

  Catalytically active particles (2): A wide range of catalytically active materials can be used. Suitable catalysts include compounds that react with the blowing agent to form a gas. The choice of catalyst depends on the blowing agent used.

When peroxide is used as blowing agent, catalyst (2) is selected from peroxide decomposers. Such drugs include
Iron-containing compounds (especially hematite (Fe ₂ O ₃ ), goethite (FeO (OH)), siderite (FeCO ₃ ), magnetite (Fe ₃ O ₄ ), iron sulfate, ilmenite (FeTiO ₃ ), very particularly hematite, Game site, sidelight),
・ Chromate (especially barium chromate),
Oxides (particularly pyrrolite (MnO ₂ ), cuprite (Cu ₂ O), magnesite (MgCO ₃ ), bauxite (Al ₂ O ₃ ), anatase (TiO ₂ ), HfO ₂ , zirconia (ZrO ₂ ), gamma Transition aluminum oxides such as alumina, or high alumina binders such as alpha bonds, very particularly pyrrolcite),
・ Manga Knight (MnO (OH)),
・ Calcium hypochlorite,
Manganese salts (especially KMnO ₄ , MnSO ₄ , C ₄ H ₆ MnO ₄ , very particularly potassium permanganate),
・ Potassium iodide,
Catalase,
Silicate (special willemite (Zn ₂ SiO ₄ )),
· _P 2 _{O 5} is included.

A particularly preferred catalyst is manganese (IV) oxide, which is either a naturally occurring mineral such as synthetic MnO ₂ or pyrrolousite.

  Due to their different functions, particles (2) and (1.1) are different. Particles (1.1) are modified with amphiphilic molecules (1.2) to stabilize the bubbles, while particles (2) are not modified to allow their catalytic properties.

pH adjuster (3): A wide range of known adjusters including acids, bases, and buffer systems can be used. The choice of pH adjuster depends on the intended use. Suitable pH adjusters are
Hydroxides (especially NaOH, KOH),
Inorganic acids (especially HCl, HNO ₃ ),
・ Fruit acid (especially citric acid, tartaric acid),
May be selected from the group of phosphates.

  The pH adjusting agents are known and are commercially available or can be obtained according to known methods.

  Additive (4): A wide range of additives known in the art can be used. Additives include accelerators and retarders for the curing reaction of the hydratable material. Examples of the hydration accelerator include calcium salts (such as calcium chloride and calcium nitride), lithium salts and lithium hydroxide, triethanolamine, and Signit. Examples of hydration retarders include citric acid, cellulose, letterdan, sugars, tartaric acid, and salts thereof.

  Additives further include dispersion aids such as polycarboxy ethers, citric acid, viscocrete, melamine sulfonate, naphthalene sulfonate, and lignin sulfonate.

  Additives further include rheology modifiers such as cellulose and cellulose derivatives, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, polyethylene glycol, xanthan gum, bentonite, microsilica, fine calcium carbonate.

  The above additives are known and are commercially available or can be obtained according to known methods.

  Amount: The amount of components (1)... (4) in the granular composition of the invention can vary over a wide range and depends in particular on the intended use and the particular component selected. Suitable amounts can be determined by routine experimentation.

  In an advantageous embodiment, the present invention relates to a composition in which the amount of (1) is in the range of at least 20%, preferably at least 40%, most preferably at least 60% of the total particulate composition.

  In a further advantageous embodiment, the invention provides that the amount of (2) is 0.2 to 80%, preferably 0.2 to 60%, most preferably 0.2 to 40% of the total particulate composition. Relates to compositions in the range. This range is wide since the amount of catalyst depends on the amount of blowing agent used. When high porosity is desired and lower stability is required, the amount of catalyst increases. Further, the density of the catalyst (2) and the density of the particles (1) may vary twice, and the range may be expanded. However, identifying an appropriate amount of catalyst (2) is within the routine work of those skilled in the art.

  In a further advantageous embodiment, the present invention relates to a composition in which the amount of (3) is in the range of 0 to 10%, preferably 0 to 5%, based on the total particulate composition.

  In a further advantageous embodiment, the present invention relates to a composition wherein the amount of (4) is in the range of 0-30%, preferably 0-20%, more preferably 0-10% with respect to the total particulate composition. .

  In one embodiment, the amount of (1) and (2) is up to 100% in total, and in a further embodiment, the amount of (1), (2), (3), and (4) is The maximum is 100% in total.

The amount of amphiphilic molecules (1.2) on the particles (1.1) can vary over a wide range. Suitable ranges include 0.5-160 μmol (1.2) / m ² particles (1.1), preferably 3-90 μmol (1.2) / m ² particles (1.1), more preferably 5 ˜60 μmol (1.2) / m ² particles (1.1) are included.

  The amount of amphiphilic molecules (1.2) on the particles (1.1) can vary over a wide range. Suitable ranges include 0.1 to 20% (1.2) relative to particles (1.1), preferably 0.4 to 12% (1.2 relative to particles (1.1). ), More preferably 0.8 to 7% (1.2) with respect to the particles (1.1).

  The amount of the composition of the invention used to foam a given amount of starting material can vary over a wide range. A suitable amount is a composition according to the invention in the range of 0.2-50%, preferably 0.2-30%, more preferably 0.5-20%, based on the dry weight of the starting material (5). It is.

The granular composition (ic) of the present invention may exhibit the following beneficial properties:
It allows foaming of mineral suspensions (sm) that tend to thicken or solidify during chemical and / or physical modification.
-It promotes foam formation, especially controlled foam formation, of chemically foamed mineral slurries.
It defines the foam stability throughout the manufacturing process.
It allows control of foam expansion rate and foam microstructure.
It leads to a foam microstructure that is homogeneous and without gradients.
It is a ready-to-use mixture and its addition can be integrated into conventional production processes.
It does not interfere with or essentially does not interfere with the hydration reaction of construction materials. Consequently, the onset of curing is not affected when the composition of the present invention is added.
• It leads to low concentrations of combustible substances in the final product.
It is economical and easy to manufacture.
It is a dry composition that is easy to transport and shows a long shelf life.

In a second aspect , the present invention relates to a process for producing the composition described herein as the first aspect of the present invention. This aspect of the invention is described in further detail below.

  The raw material particles (1.1), amphiphilic molecules (1.2), catalytically active particles (2), pH adjuster (3), and additive (4) are commercially available or known Can be obtained according to the method.

  Homogeneous mixing of particles (1.1), short chain amphiphilic molecules (1.2), and catalytically active particles (2) with additional additives (3), (4) in a suitable apparatus is achieved. To obtain a catalytically active foam-forming powder. Accordingly, the method of the present invention includes the step of combining the appropriate amounts of raw materials to obtain the solid particle composition described herein. The combination of raw materials can be achieved by known methods. Suitable methods include feeding the raw material to a ball mill and grinding the material for a long period of time. A suitable mixing time is 1 to 100 hours, preferably 12 to 24 hours.

  In an advantageous embodiment, the process is carried out dry, i.e. without adding solvent to the reaction system. It is surprising that the particles (1.1) are easily homogenized and fully hydrophobized by mixing them with amphiphilic molecules (1.2). This avoids the use and removal of solvents and makes manufacture simple and reliable.

In a third aspect , the present invention relates to the use of the composition described herein (first aspect) in the manufacture of a foamed construction material such as foamed cement. This aspect of the invention is described in further detail below.

As already discussed above, the composition of the present invention is suitable for generating foam in the presence of a blowing agent. They can therefore be used to generate mineral foams. Such mineral foams can be used as construction materials and thus include cement mineral foams. As such, the present invention provides the use of the compositions described herein as ready-to-use products for the manufacture of foam construction materials, particularly foam cement.

  The term blowing agent refers to any material that is known and releases a gas, such as oxygen, nitrogen, hydrogen, or carbon dioxide, under appropriate conditions.

  Oxygen releasing compounds include carbamide peroxide, sodium percarbonate, peroxo compounds such as peroxomonosulfuric acid and disulfuric acid, chloric acid and perchloric acid and their salts, alkali or alkaline earth peroxides such as sodium peroxide And related compounds such as potassium peroxomonosulfate and sodium peroxodisulfate.

  Hydrogen releasing compounds include, for example, aluminum in the form of a powder, chip, sprint or as a paste. In an aqueous alkaline environment such as is typically present in cementitious compositions, Al oxidizes to form aluminum hydroxide species and hydrogen. This is summarized in the following simplified reaction scheme: 2Al + 6H2O → 2Al (OH) 3 + 3H2.

  Nitrogen releasing compounds include azodicarbonamide and modified azodicarbonamide.

  Carbon dioxide releasing compounds include isocyanates and diisocyanates, alkali and alkaline earth carbonates, alkali and alkaline earth bicarbonates, ammonium carbonate, ammonium bicarbonate.

  Preferred blowing agents include peroxides such as hydrogen peroxide.

  Foamed construction materials can be tailored to the specific needs of the end user by selecting the appropriate inventive composition.

  First, porosity can be affected. In the case of foam cement, a porosity of up to 98% by volume can be achieved. Important parameters are the amount of blowing agent and the composition of the catalytically active foam-forming powder.

  Second, the type of pores can be affected. Foamed construction materials may exhibit a predominantly open structure or a predominantly closed structure. An important parameter is the amount and composition of the catalytically active foam-forming powder.

  Third, the pore size distribution can be affected. Typically, the end use targets a narrow and homogeneous diameter distribution. This is an inherent property provided by the composition of the present invention.

In a fourth aspect , the invention relates to a process for producing a foamed construction material (fcm) using the composition (ic) described in the first aspect of the invention. . This aspect is described in more detail below and is also illustrated in FIG.

  The disadvantages of the prior art discussed above are overcome by applying the ready-to-use product (ic) of the present invention. It simplifies the process involved in foaming by mixing a defined amount of the composition of the invention with the starting material (sm) to be foamed. The addition can take place before, during or after dispersion of the starting material. In the final step, a suitable blowing agent (ba) is injected to initiate foaming.

  As such, the compositions of the present invention are compatible with existing equipment and can be applied directly without further education of the relevant construction workers.

  A wide variety of starting materials can be used due to the foam stability obtained when using the compositions of the present invention. There are no restrictions on systems with a short cure start. Rather, the naturally occurring onset of curing of the starting material is consistent with the composition of the present invention.

  In contrast to the known foamable products, the ready-to-use products of the present invention do not extend the onset of cure. This minimizes the loss of strength and durability of the foamed product.

  As a result, a process for producing foamed construction materials is provided that has (a) increased process robustness and (b) improved product quality and reliability compared to known methods. .

In order to further illustrate the present invention, the following examples are provided. These examples are provided without intending to limit the scope of the invention.

Example 1: Calcium aluminate foam Example 1.1: Solid pore composition with closed pore structure (product ready for use):
The weight ratios of the constituent components are as follows.
97.56% microsilica 1.33% heptylamine 1.02% manganese oxide

  A 500 mL low density polyethylene grinding bottle containing 230 g of 15 mm diameter alumina grinding balls is filled with microsilica, heptylamine and manganese oxide and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
The calcium aluminate foam is prepared from the following raw material composition expressed in weight percentages.
65.23% calcium aluminate powder 38.88% water 3.75% foam forming powder 0.11% lithium carbonate 1.04% hydrogen peroxide (50% solution)

  The foam-forming powder is placed in a beaker containing water and homogenized by vigorously stirring the suspension. The suspension is then cooled to 5 ° C., calcium aluminate powder is added and the suspension is stirred again until homogeneity is achieved. Then, lithium carbonate is mixed. After stirring for 2 minutes, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The prepared wet foam is stable until a cement hardening reaction occurs after 42 minutes and the foam solidifies. The calcium aluminate foam is stored in a humid atmosphere for 2 days to allow for proper curing. Thereafter, it is removed from the mold and dried.

result:
The resulting calcium aluminate foam portion exhibits a diameter of 120 mm and a height of 60 mm. Its density is 336 kg / m3. This is believed to be an unusually low density for calcium aluminate foams. The median pore diameter is 0.72 mm, the 10% quantile is 0.21 mm, and the 90% quantile is 1.48 mm. The foam mainly exhibits closed pores.

Example 1.2: Open pore structure solid particle composition (product ready for use):
The weight ratios of the constituent components are as follows.
97.47% alumina powder (CT3000SG)
1.33% propyl gallate 1.02% manganese oxide

  A 500 mL low density polyethylene grinding bottle containing 305 g of 15 mm diameter alumina grinding balls is filled with alumina powder, propyl gallate and manganese oxide and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
The calcium aluminate foam is prepared from the following raw material composition expressed in weight percentages.
54.48% calcium aluminate powder 37.43% water 6.49% foam forming powder 0.60% lithium carbonate 1.00% hydrogen peroxide (50% solution)

  15. Place the foam-forming powder in a beaker containing water having a NaOH concentration of 25. 5 mMol / L. Homogenize the effervescent powder and water by vigorously stirring the suspension. The suspension is then cooled to 5 ° C., calcium aluminate powder is added and the suspension is stirred again until homogeneity is achieved. Then, lithium carbonate is mixed. After stirring for 2 minutes, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The prepared wet foam is stable until a cement hardening reaction occurs after 50 minutes and the foam solidifies. The calcium aluminate foam is stored in a humid atmosphere for 2 days to allow for proper curing. Thereafter, it is removed from the mold and dried.

result:
The resulting calcium aluminate foam portion exhibits a diameter of 120 mm and a height of 55 mm. Its density is 367 kg / m3. This is believed to be an unusually low density for calcium aluminate foams. The median pore diameter is 0.26 mm, the 10% quantile is 0.12 mm, and the 90% quantile is 0.52 mm. The foam exhibits an open pore structure.

The following table summarizes the results obtained.

Example 2: Portland cement foam (w / z 0.55)
Example 2.1: Small pore solid particle composition (ready-to-use product):
The weight ratios of the constituent components are as follows.
82.447% calcium carbonate,
13.592% manganese oxide,
3.960% heptanoic acid

  A 500 mL low density polyethylene grinding bottle containing 250 g of 15 mm diameter alumina grinding balls is filled with all components and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
Cement foam (CEM I, 52.5) is prepared from the following raw material composition indicated by weight:
58.859% cement,
32.427% water,
6.433% foam-forming powder,
2.280% hydrogen peroxide (50% solution)

  The foam-forming powder is placed in a beaker containing water and homogenized by vigorously stirring the suspension. This suspension is then added to the cement powder with stirring. After 10 minutes of stirring, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The cement foam is removed from the mold after 4 days and then dried.

result:
The prepared wet foam is stable. The onset of curing occurs 2.40 hours after adding water to the cement powder. The resulting cement foam part is characterized by dimensions of 200 mm × 200 mm × 50 mm. Its density is 173 kg / m3. This is believed to be a very low density for Portland cement foam. The pore structure is uniform with no gradient. The median pore diameter is 0.82 mm, the 10% quantile is 0.34 mm, and the 90% quantile is 1.35 mm.

Example 2.2: Large pore solid particle composition (product ready for use):
The weight ratio of the constituents is as in Example 2.1.
A 500 mL low density polyethylene grinding bottle containing 250 g of 15 mm diameter alumina grinding balls is filled with all components and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
Cement foam (CEM I, 52.5) is prepared from the following raw material composition indicated by weight:
60.628% cement,
33.391% water,
3. 683% foam forming powder,
2.299% hydrogen peroxide (50% solution)

  The foam-forming powder is placed in a beaker containing water and homogenized by vigorously stirring the suspension. This suspension is then added to the cement powder with stirring. After 10 minutes of stirring, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The cement foam is removed from the mold after 4 days and then dried.

result:
The prepared wet foam is stable. The onset of curing occurs 2.74 hours after adding water to the cement powder. The resulting cement foam part is characterized by dimensions of 200 mm × 200 mm × 50 mm. Its density is 174 kg / m3. This is believed to be a very low density for Portland cement foam. The pore structure is uniform with no gradient. The median pore diameter is 1.64 mm, the 10% quantile is 0.45 mm, and the 90% quantile is 2.57 mm.

Example 2.3: Foam stable solid particle composition (product ready for use):
The weight ratio of the constituent components of the catalytically active foam-forming powder is as follows.
82.447% calcium carbonate,
13.592% manganese oxide,
3.960% heptanoic acid

  A 500 mL low density polyethylene grinding bottle containing 250 g of 15 mm diameter alumina grinding balls is filled with all components and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
Cement foam (CEM I, 52.5) is prepared from the following raw material composition indicated by weight: In order to monitor the stability of the foam over time, Mape Mapard D is used to retard the curing reaction.
58.769% cement,
31.356% water,
1.175% retarder 6.423% foam-forming powder,
2.277% hydrogen peroxide (50% solution)

  The foam-forming powder is placed in a beaker containing water and homogenized by vigorously stirring the suspension. This suspension is then added to the cement powder with stirring. After 10 minutes of stirring, the suspension starts to foam by adding hydrogen peroxide. The slurry so obtained is poured into a transparent cylindrical mold (12 cm diameter and 30 cm height) and completely filled with foam. The stability of the foam is monitored over time by taking a picture of the sample every 2 minutes.

result:
The prepared wet foam was still soft 7 hours after adding water to the cement. During this time, the foam did not experience changes in its microstructure (pore size distribution, density), no gradient was formed, and the change in foam height was less than 5%.

Example 2.4: Using foam-forming powder without amphiphilic molecules (comparative example not according to the invention)
Solid particle composition (lack of amphiphilic molecules (1.2)):
The weight ratios of the constituent components are as follows.
85.847% calcium carbonate,
14. 153% manganese oxide,

  A 500 mL low density polyethylene grinding bottle containing 250 g of 15 mm diameter alumina grinding balls is filled with all components and ground for 18 hours. The homogenized powder is then poured into a beaker. The grinding balls are held from the residue by a polymer sieve and washed.

Foam preparation:
Cement foam (CEM I, 52.5) is prepared from the following raw material composition indicated by weight:
60.476% cement,
33.307% water,
3.924% foam-forming powder,
2.293% hydrogen peroxide (50% solution)

  The foam-forming powder is placed in a beaker containing water and homogenized by vigorously stirring the suspension. This suspension is then added to the cement powder with stirring. After 10 minutes of stirring, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The cement foam is removed from the mold after 4 days and then dried.

result:
The prepared wet foam is unstable and already disintegrates during foaming. The onset of curing occurs 2.74 hours after adding water to the cement powder. The resulting cement foam part is characterized by dimensions of 200 mm × 200 mm × 25 mm. Its density is 690 kg / m3. Its pore structure is very heterogeneous with very large pores and even fine pores, with gradients.

Example 2.5: No hydrophobized particles (comparative example not according to the invention)
Foam preparation:
Cement foam (CEM I, 52.5) is prepared from the following raw material composition indicated by weight:
62.418% cement,
34.376% water,
0.888% manganese oxide,
2. 317% hydrogen peroxide (50% solution)

  Place manganese oxide in a beaker containing water and homogenize the suspension by vigorous stirring. This suspension is then added to the cement powder with stirring. After 10 minutes of stirring, the suspension starts to foam by adding hydrogen peroxide. The slurry thus obtained is poured into a mold in which expansion of foam progresses until decomposition of hydrogen peroxide is completed. The cement foam is removed from the mold after 4 days and then dried.

result:
The prepared wet foam is unstable and already disintegrates during foaming. The onset of curing occurs 3.06 hours after adding water to the cement powder. The resulting cement foam part is characterized by dimensions of 200 mm × 200 mm × 20 mm. Its density is 804 kg / m3. Its pore structure is very heterogeneous with very large pores and even fine pores, with gradients.

Conclusion:
The following table summarizes the results obtained, in all cases the starting material is Portland cement and the sample size (mm) is rectangular, 200 × 200 × 50.

Considering Example 2 and comparing experiments 2.1, 2.2, 2.3, 2.4, and 2.5 performed individually, the following can be concluded:
@ 2.1: By using 10.93% by weight of the composition according to the invention (based on dry material), a foam with micropores is obtained.
@ 2.2: By using only 6.07 wt% (not 10.93 wt%, ie 1/2 of (1)), a homogeneous foam with greatly increased pore size is obtained. It is done. Reducing the amount of the composition of the present invention does not affect the onset of curing or the density of the final component.
@ 2.3: By using the composition of the present invention, a stable cement foam is prepared for over 7 hours. As a result, foams with highly controlled microstructure and properties are achieved and rapid curing is not necessary for their production.
@ 2.4: By omitting the amphiphilic molecule (1.2), a stable foam cannot be obtained. Furthermore, the density is higher and the pore structure is less uniform. The onset of curing is not affected or is not significantly affected.
@ 2.5: A stable foam cannot be obtained by omitting the hydrophobized particles (1). Furthermore, the density is much higher and the pore structure is less uniform. The onset of curing is not affected or is not significantly affected.

  Overall conclusion: Amphiphilic molecules (1.2) combined with particles (1.1) are very important to obtain stable foams with controlled microstructure. The amphiphilic molecules (1.2) combined with the particles (1.1) do not affect the onset of curing.

Claims (11)

A solid particle composition comprising a first particle group (1) and a second particle group (2),
The first particle group (1) is
Selected from the group consisting of oxides, hydroxides, carbides, nitrides, phosphates, carbonates, silicates (1.1),
The surface of the particle is modified with an amphiphilic molecule (1.2) comprising at least one head group and one tail group;
The tail group is selected from an aliphatic or aromatic group or cyclic group having 2 to 8 carbon atoms and optionally one or more substituents;
The head group is selected from phosphate, phosphonate, sulfate, sulfonate, alcohol, amine, amide, pyrrolidone, gallate, carboxylic acid;
The second particle group (2)
Catalytically active particles adapted to react with the blowing agent to form a gas;
Selected from the group consisting of iron-containing compounds, chromates, oxides, silicates, Ca (OCl) ₂ , KI, KMnO ₄ , catalase, P ₂ O ₅ ;
The amount of (1) is in the range of 20.0 to 99.8% and / or the amount of (2) is in the range of 0.2 to 80%;
Solid particle composition wherein the amount of amphiphilic molecules (1.2) on the particles (1.1) is in the range of 0.5-160 μmol (1.2) / m ² particles (1.1) object. Preferably in the form of a powder having a particle size of 30 nm to 300 μm,
The composition according to claim 1, which is preferably in the form of a granular material having a granule diameter of 0.5 to 20 mm. further comprising a pH adjusting agent (3) and / or an additive (4),
The pH adjuster (3) is selected from the group consisting of acids, bases, and mixtures (buffers) thereof;
The composition according to claim 1 or 2, wherein the additive (4) is selected from the group consisting of accelerators, retarders, dispersion aids, rheology modifiers.   4. A composition according to any one of claims 1 to 3, wherein the head group is selected from carboxylic acids, gallates and amines. The iron-containing compound is selected from the group consisting of hematite Fe2O3, goethite (FeO (OH)), siderite (FeCO3), magnetite (Fe3O4), iron sulfate, ilmenite (FeTiO3);
The chromate is selected from the group consisting of barium chromate;
The oxide is selected from the group consisting of pyrrolite (MnO2), cuprite (Cu2O), magnesite (MgCO3), bauxite (Al2O3), anatase (TiO2), HfO2, zirconia (ZrO2), transition aluminum oxide;
-The composition according to any one of claims 1 to 4, wherein the silicate is selected from the group consisting of willemite.   A method for producing a composition according to any one of claims 1 to 5, comprising particles (1.1), amphiphilic molecules (1.2), catalytically active particles (2), optional Combining a pH adjusting agent (3) and optionally further additives (4).   The method of claim 6, wherein the materials are combined without further diluent / solvent.   Use of a composition according to any one of claims 1 to 5 as a ready-to-use product for producing a mineral foam.   Use according to claim 8, wherein the mineral foam is a foamed construction material.   Use according to claim 9, wherein the foam construction material is foam cement.   A ready-to-use foam-forming powder comprising the composition according to claim 1.